The invention concerns a burner for burning liquid or gaseous fuels.
A burner of this type is known (U.S. Pat. No. 4 347 052) in relation to separating the combustion air into primary, secondary, and tertiary air and to supplying the tertiary air through a separate air box in order to decrease the formation of nitrogen oxides during combustion. Supplying flue gas to where the flame begins between the release of the primary air and of the secondary air in burners with a central oil lance and a tripartite air release is also known (German OS No. 3 327 597). Problems sometimes occur, however, in the known burners that are equipped with a central fuel lance and operate with heavy oil when they operate in a narrow burner space, in a fire-tube three-pass boiler for example, in that low-pollutant combustion can be associated with an impermissibly high ejection of solids.